Art of preserving valuable elements of organic materials in dry storage



Nov. 21, 1944. ARNOLD ART OF PRESERVING VALUABLKE ELEMENTS OF ORGANIC MATERIALS IN DRY STORAGE Filed Oct. 3, 1941 3 Sheets-Sheet 1 INVENTOR Q GEEHA'D D. Qfih/QLD MAM/{AMA AT TOENEYS Nov. 21, 1944. a. D. ARNOLD 2,363,037

ART OF PRESERVING VALUABLE ELEMENTS OF ORGANIC MATERIALS IN DRY STORAGE Filed Oct. 3, 1941 3 Sheets-Sheet Z IN ENTOR: GEEQ4DD.IQEN04D ATTORNEYS,

Patented Nov. 21, 1944 ART OF PRESERVING VALUABLE ELEMENTS OF ORGANIC MATERIALS IN DRY STOR- AGE Gerald D. Arnold, Wauwatosa, Wis. Application October 3, 1941, Serial No. 413,420

"portant considerations in a device of this char- 12 Claims.

This invention pertains to improvements in the art of preserving valuable elements of organic materials in dry storage. The present application is a companion to my applications Serial No. 231,110,filed September 26, 1938, now Patent No. 2,241,654 of May 13, 1941, and Serial No. 311,639 filed December 29, 1939, now Patent No. 2,266,292 of December 16, 1941. 3

The major objects of the present invention are the same as those specified in the companion applications above identified, viz.'--the preservation of color'and vitamin content, during extended storage periods, in organic materials which have become highly heated as in dehydration or otherwise. The invention also has for its objective a method in which a product initially highly heated may be cooled as well as dehydrated by the passage of a cold gas across it. Whle the invention has particular reference to herbaceous foods, it has a wider application to animal as wellas vegetable foods for consumption by human beings aswell as by stock and fowl. Even more broadly, the invention applies to the retention of valuable ingredients in any organic product, one particularly valuable application of the invention involving the dissipation of heat from fertilizers following dehydration.

Heat, suflicient to cause degeneration, may be imparted to organic material by the atmosphere or it may be generated during the process of cutting, dehydration, or grinding. If'this heat is allowed to remain in the material during extended storage periods, it promotes fermentation, oxidation, and enzymetic and bacterial action to the detriment of the product.

The present invention contemplates an organization in which heat transfer from the material to the air is direct, without any intervening partition of any nature, the arrangement, however, being such that the material to be chilled is mechanically propelled and agitated where necessary, thus adapting the cooling operation to a variety of materialswhich may not be of such a. nature that they can be pneumatically conveyed :n the cooling currents as contemplated in my uniformity of the output being one of the imacter.

Even when the cooling medium comprises saturated chilled air, there is practically no absorption of moisture by the product being treated.

In fact, the converse is true and, in many instances, the product is further dehydrated while being chilled. The reaso'n for this lies' in the fact that the material is hot and dry and the heat imparted therefrom to the refrigerated air re: duces the relative humidity of the air so that the air becomes a drying medium even though initially saturated. Until the material becomes as cold as the air, there is no possibility of the conbe used in any desired order or relationship.

Other objects will be apparent to those skilled in the art upon the following disclosure of the invention in which:

Figure 1 shows diagrammatically in side elevation a device embodying the invention partially broken away to expose its interior structure.

Figure 2 is a detail view taken in cross section on line 2-.-2 of Figure 1.

Figure 3 is a View largely in longitudinal sec-,

tion through an alternative embodiment of the,

invention, portions of the conveyor troughs being broken away.

Figure 4 is a detail view taken on line 4-4 of Figure 3.

Figure 5 is a plan view of the apparatus shown in Figure 3 and Figure 4 as appears on a reduced scale.

Figure 6 is a View largely in longitudinal section to a further modified embodiment of the invention.

Figure 7 is a detail view taken in section on the line |-'l of Figure 6.

Like parts are identified by the same reference characters throughout the several views.

In the device shown in Figure 1, :a screw conveyor 8 of the mutilated thread type is provided in any desired length in a conveyor trough 9. The particular type of conveyor thread or paddle In fact, the several devices may v will be determined by the nature of the material handled ,and will further involve the question whether it is desired that the material be tossed or agitated in the air stream during conveyor movement. It further involves the question whether the desired material be conveyed rapidly, in which case a longer conveyor and trough will ordinarily be required, or whether the conveyor will be designed to retard the movement of the material in order to accomplish more cooling in given distance traveled.

In the device shown in Figure 1, the trough 8 is provided with a cover l enclosing the trough to constitute a closed chamber in which prechilled refrigerating gases are circulated. Preferably, the refrigerant will comprise ordinary air, cooled by passage over an evaporating radiator II in a refrigerating system which comprises the compressor l2, condenser l8, reducing valv l4 and return pipe II. The air cooled by passage over the radiator H is delivered directly into refrigerating chamber as defined by the trough 8 and its top closure i0. Leaving the chamber l0 through manifold ii, the air passes to the circulating fan I! under which it'is delivered into a cyclonic separator i8 in order that dust, which the air may have derived from the material being chilled, may be segregated from the air and returned to the chilling chamber through the conduit l8.

If the air is still colder than surrounding atmospheric air, it may be recirculated through pipe 20 back to the radiator Ii. The use of this pipe is optional, as frequently the efficiency of the apparatus is such, with reference to atmospheric conditions, that the air is substantially as warm as atmospheric air when released from the dust separator i8.

The material to be chilled is delivered in finely comminuted form through pipe into pipe i9. Both the freshly introduced material and the dust returned from separator l8 pass into the rotary charging valve 26 driven by belt 21 from motor 28 through a speed changer 28 subject to regulation by a control mechanism 30. According to the rate at which the rotary charging valv 26 is turned, the finely divided produce or other material to be chilled is discharged into the hopper 82 which deliver it into the path of the conveyor 8.

The conveyor is driven by belt 38 from motor 34 through a speed changer 35 having control mechanism at 36. Each of the controls may comprise a fluid pressure diaphragm to which pressure is communicated through pipes 38 and 39 from a source (not shown) subject to control of a thermostatic valve mechanism 40 which is exposed to the temperature of the air withdrawn.

from the refrigerating chamber by fan IT. This general type of control is well known and hence is not illustrated in more detail. As specifically used in this device, it is so connected that if the temperature of the discharged air rises above the fixed value at which the thermostatic valve 40 is set, the control will function to effect a relative reduction in the rate of rotation of the charging valve 26 and a corresponding reduction in the stant temperature of output is maintained to keep the product uniform.

The chilled product, after being propelled by conveyor 8 through the refrigerating chamber 8.

I0, is discharged through pipe 42 to sacking outlets 43, 44 which may be located on a lower floor. This device, in which the mutilated thread conveyor'tosses the material into the path of the refrigerating air stream, or at least agitates the material in the conveyor, is peculiarly well adapted to handle finely divided meal and the like.

The device shown in Figure 3 is particularly intended to operate on similar material, and also is received in the input end of the first of a series of conveyor troughs 90, 8| and 82 in which operate screw conveyors 80, 8| and 82. These conveyors have continuous threads as clearly shown in Figure 3, but the threads are provided at suitable intervals with radial bucket flanges 84 having rounded margins to agitate and lift the material without catching thereon. The conveyors are turned in alternately opposite directions by the driving chain 830 which is driven by,

chain 88l from motor 840 through a speed changer 350 controlled by the regulating mechanism 380. The regulating mechanism 860 is actuated by pressure communicated to it through pipe 380 subject to the control of a thermostatic valve.

mechanism 400 which derives pressure through pipe 890 from a suitable source (not shown). The pressure line 380 from the valve mechanism 400 also extends to the pressur responsive regulating mechanism 800 which controls the rate at which the rotary charger 46 is operated. Thus, a rise in the temperature of the discharged air is made automatically to retard the rat of operation of the charger and the several conveyors, while a reduction in the temperature of the discharged air is made automatically to accelerate the rate of operation of the charger and the several conveyors with the result that the material is discharged at a uniform temperature. After the material passes through the whole length of trough 80, it falls through the discharge pipe 48 into trough 9|. After passing from right to left .(Fig. 3) through trough 9|, the material is discharged through pipe 48 into trough 92. After passing through this trough, it emerges from the casing I00 through pipe 50 for sacking or storage.

The cooling radiator shown in more detail in Figure l is here only diagrammatically indicated at H0. The air drawn therethrough passes by means of pipe 5| into the refrigerating chamber I00, filling such chamber so that as. the material is agitated in the several feed troughs it comes into direct contact with the refrigerating air to be' chilled thereby. The admission 5| is preferably expanded as shown by the plan view in Figure 5 to. avoid the localizing of drafts in the chamber I00.

The air, after having received heat from the In this instance, no means is provided for dust separation since the finely divided or chopped stringy material to be refrigerated is here passing pressed open by the hay.

2,363,037 i through relatively quiescent air as compared with y the more rapidly moving and concentrated stream r air in the chamber a, II of Figure 1. It will, of course, be understood that a return pipe from blower I10 to the evaporator radiator or other chilling radiator of unit H0 may be provided in material mustbe ilnelyv divided to be handled by the devices of Figures 1 and 3. The de'viceof,

. Figure 6 is well adapted to handle loose or coarsely chopped hay which is forked or'fed by hand into the hopper inlet 250, past the valve 2H, this valve being biased by a weight 282 toward a nor,- mally closed position from which it may be The refrigerating chamber "H is provided with a belt conveyor 93 operating over pulleys 94 and 95, the latter being driven by belt 332 on the motor 342 through a speed changer 352 controlled by the regulating mechanism 362. The pressure line 382 con trolled by the thermostatic valve mechanism 402 andsupplied with pressure by a pipe 392 from a suitable sourceinot shown) actuates the control mechanism 362 and also actuates a gage 363 .ance with output air temperature at the thermo stat 402. as was explained in connection with Figure 1 and Figure 3.

The air chilling radiating apparatus Ill receives and cools the air admitted through duct 5| 2 into the refrigerating chamber NH. The

chamber is provided with bafiles at 56 and 51 which alternate above and below the path of movement of the hay on the upper flight of conveyor 93. These baflies cause the air to circulate through the hay as shown by the arrows in Figure 6. passing first upwardly and then downwardly through the layer of hay carried by the foraminous conveyor 93 until finally the air, after absorbing heat from the hay, passes through the outlet pipe I62 to the exhaust fan I12 by which the air is either expelled from the apparatus or recirculated, as suggested in Figure l.

The conveyor 93 may conveniently be provided with propelling cleats 60 which not only assure the movement of the hay with the conveyor but further wipe from the bottom of chamber IN The hay conveyor 93 is, howof an exhaust fan, but I also contemplate that the air may be driven throughthe system under pressure, if desired. The advantage of using an exhaust fan rather than a pressure fan for air circulation is that the reduced pressure involved in the use of the suction fan facilitates further dehydration of the product, where this is desired.

In general, the product, for the most effective practical preservation of its vitamin content, will be chilled approximately to 60 degrees Fahrenheit. Chilling much below 60 degrees is uneconomical, since main vitamin losses occur at temperatures materially in excess of 60 degrees." Moreover, too cold a product, with reference to' the atmosphere, will condense moisture from the atmosphere tending to cause moldor spoilagepf v the product, at least at its surface.

the accumulations of dust which have sifted through the foraminous conveyor belt 93. The cleats 60 deliver this dust in successive installments to a dischar e pipe 62.

It will, of course, be understood that instead of the mechanical refrigeration devices indicated, the air may be chilled by passing cold water from any convenient natural or artificially cooled source, through the air chilling radiators H, I I0 The device shown'in Figure 6 minimizes carotin' and other vitamin losses in that it is capable of handling the unchopped product. The finer the product is ground, the faster the carotin. loss in storage under comparable temperature conditions. Many changes can be made in the apparatus without wholly departing from the invention as herein disclosed. For example, the chilling air may travel through the apparatus in the same direction as the food to be chilled, but a more efficient means of heat transfer is provided by counter-currentmovement as herein disclosed. In any case, the refrigerating gases are preferably confined in a closed space through which the food to be chilled is passed at a rate which depends upon the temperature of the gases emerging from the closed space. I also prefer a to use an exhaust fan rather than a pressure fan for circulating the cooling medium over the food product, at least, in cases where the product is dehydrated, or where dehydration is desirable, for I found that, contrary to expectation, a very substantial dehydrating effect is achieved by circulating cold gases over a hot product. In practically every instance, it may be'assumed that the product treated in accordance with the present invention is initially heated materially in excess of atmospheric temperatures.

I claim:

1. A method for the purposes described including the advance of highly heated finely divided organic material upon a given path, the con-, tinuous circulation of a refrigerating-gas in a closed circuit including a, portion of said path, the segregation from gas leaving said circuit of dust bornethereby, return of such 'dust to said path, and the rechilling of the refrigerating gas 'before the return in said circuit to said path portion.

2. In a device oi the character described for the treatment of material including substantial quantities of fines, and saving the fines, said device comprising a closed circuit endless gas conduit including a gas-temperature-modifying chamber having temperature modifying means therein, a treatment chamber, and a separating chamber in series, means for introducing material to be treated into said endless conduit at one side of the treatment chamber and removing material therefrom at the other side of the treat-- ment chamber, whereby the material treated is not passed through the temperature modifying chamber, said treatment chamber including means for the advance, of such material and for the agitation and exposure of such material to gas in said conduit, means for propelling gas in substantially closed circuit through said conduit to be modified as to temperature in the chamber first mentioned and to modify in the treatment chamber the temperature of the material treated 3. In a device of the character describcd,"the combination with a conveyor for organic mate-- veyor having, flights for the agitation, lifting,

rials and means including a rate changer for the 1 1 means for adjusting said speed changing device actuation thereof, of a closed chamber in which said conveyor operates, said chamber being provided with inlet and outlet means for the material to beconveyed and with inlet and outlet means for a refrigerating gas, a cooler for the refrigeration of gas, means for circulating a refrigerating gas through said cooler and said chamber and across said conveyor, and regulating means for said rate changer including a thermostat disposed in the path of gas which has traversed said conveyor and provided withoperative connections for the adjustment of said rate changing means to increase the rate of conveyor movement in accordance with the decrease of temperature to which said thermostat is subject.

"4'. In a device of the character described, the combination with a conveyor for organic material and means including a rate changer for the actuation thereof, of'a closed chamber in which the conveyor operates, said chamber being provided with inlet and outlet means for the material to be conveyed and with inlet and outlet means for refrigerating gas, means for circulatascaosr treatment of material, said device including a conduit comprising a treating chamber, means for impelling gas through said chamber, means for the admission and discharge of material to be modified as to temperature by the gas iii-the chamber, said chamber including a screw conpropulsion, and exposure of the'material in said chamber to the gases impelled therethrough, drlvconnections for the rotation of said screw conveyor including a speed changing device, and

including a thermostat exposed to gases which have acted on material in said chamber and having connections for the movement of the speed changing device to accelerate and deceleraie the rotation of said screw conveyor in a predetermined manner-related to the temperature of the gas to which the material treated has been exposed.

. :1. a device of the character described comprising a closed gas circulating system including a dust separator, gas refrigerating means, a treatment chamber, gas propelling means, and suitable connections for delivering refrigerated gas from said refrigerating means to said chamber .for cooling said material therein and thence mg a refrigerating gas through said chamber and across said conveyor, regulating means for said rate changer including a thermostat disposed in the path of gas which has traversed said conveyor, said thermostat being provided with operative connections for the adjustment of said rate,

changing means to increase the rate of conveyor movement in accordance with the decrease of temperature to which said thermostat is subject, together with means for delivering to the conveyor material to be propelled thereby, driving connections for said delivering means including a rate changer, and control mechanism for said last mentioned rate changer including means for the actuation thereof from said thermostat concurrently with the actuation of the rate changer in the driving connections to the conveyor.

5. A device of the character described for the cooling of material including substantial quantitles of fines, and saving the fines, said device comprising a closed gas circulating system including a separator having a continuously eilective capacity adequate for removal of fines from means for introducing material into said system,

and removing material therefrom, and means for returning to and distributing in said material the fines which are removed in the separator from the circulating gas.

- 6. A device of the character described for the through said separator and back to said refrigerating means, a conveyor in said chamber, means for delivering said material to said conveyor and receiving said material therefrom, together with me regulating material input to said conveyor, driving connections for said regulating means and said conveyor including rate changing means, and controls for the rate changing means including a thermostat in said system in th path of air recently traversing said chamber and operatively connected to vary the rate veyor inversely in accord nce with the temperature of the gas to which t e thermostat is subject.

8. The device of claim 5 in which the gas propolling means comprises a suction fan, whereby dehydration as well as chilling of material traversing the treatment chamber is enhanced.

9. A device of the character described comprising a closed gas circulating system including a dust separator, gas refrigerating means, a treatment chamber, gas propelling means, and suitableconnections for delivering refrigerated gas from said refrigerating means to said chamber for cooling said material therein and thence through said separator and back to said refrigcrating means, a conveyor in said chamber, means for delivering said material to said conveyor and receiving said material therefrom, to

-gether with means controlling the delivery of material to said conveyor, said separator being provided with a return connection to said delivery controlling means and thereby to said conveyor, said delivery controlling means and said conveyor being provided with driving connections including rate changing means, and regulating means therefor including thermostatic means in the path of air leaving said chamber and connected to vary the rate of said material movement to and by said conveyor inversely in accordance with the temperature of such air, the conveyor comprising means for not only propelling but also for agitating and lifting material in said chamber in the path of said air.

10. A device of the character described comprising a closed gas circulating system including a dust separator, gas refrigerating means, a treatment chamber, gas propelling means, and suitable connections for delivering refrigerated gas from said refrigerating means to said chamber.

for cooling said material therein and thence through said separator and back" to said refrigerating means, a conveyor in said chamber, means for delivering said material to said conveyor and receiving said material therefrom, the conveyor comprising a foraminous belt and the chamber being provided above and below a material-carrying flight of said belt with staggered partitions adapted to direct gaseous flow back and forth through material on said belt flight.

11. Apparatus of the character described comprising in combination with a conveyor 9. means for the operation thereof including a rate changer, of means providing a closed chamber in which the conveyor operates, a 'gas refrigerating device, means for circulating a cooling gas through said device and said chamber and past said conveyor, and a thermostat exposed to the temperature of gas which has moved past said conveyor and provided with operative control connections to said rate changer for the adiustment thereof toward a decrease in the rate of conveyor movement-upon an increase in the temperature of such gas.

12. A device of the character described com-- prising a closed gas circulating system including a .dust separator, gas refrigerating means, a treatment chamber, gas propelling means, and suitable connections for delivering refrigerated gas from said refrigerating means to said chamber for cooling said material therein and thence through said separator and back to said refrigerating means, a conveyor in said chamber, means for delivering said material to said conveyor and receiving said material therefrom, said conveyor comprising a screw adapted to propel the material and to lift it for exposure to the gas, said screw comprising a generally helical propelling flight, and bucket webs with smoothly rotinded edges projecting laterally from said flight at intervals whereby to be adapted to lift even relatively stringy material for aeration without entangling such material.

GERALD D. ARNOLD. 

